Persian carpet can be divided so far as design is concerned into two main groups. Carpets with a geometric design and carpet with a curvilinear, known as floral carpets.

Geometric Design Carpets
All the carpets in this group decorated with linear elements composed of vertical, horizontal and diagonal lines or formed by a repetition of the same motifs.
Carpets with geometric designs are woven by nomadic tribes, with particular motives and designs. These motives facilitates the attribution of a carpet to a particular tribe or place of origin.

Curvilinear, known as floral carpets
The great feature of Persian design has always been its intricate, symbolic patterns, which have fascinated experts and art lovers throughout the world for centuries.

Yet it is asserted by many that the designs reflect not so much symbolism as the Persian's close affinity with nature and a pure love of patterns as works of art. Nature supplies the greatest inspiration to the carpet designer, although other designs are adapted from such foreign sources as China and Arabia. In all probability designs began hundreds of years ago with faithful representations of trees, flowers, birds and clouds which, through the creative and innovative genius of Persian art, became more and more stylized with each succeeding generation.

The most common motif for all Persian rugs, especially the larger ones, is a large central medallion. Yet, even if they are basically the same design, no two medallions are ever exactly the same. Some experts believe that the medallion design stems from the very religious nature of the weavers and that their inspiration probably came from the domes of the mosques.

In thinking of patterns, the great Shah Abbas invariably springs to mind as the inspiration for various patterns, all of which are inspired by the lily often in an isolated central position linked only by delicate tendrils.

Another favorite is the pine or leaf pattern, a very graceful stem with a slightly bent head, which proved the inspiration for the paisley pattern, rather stereotyped and meaningless compared with its instigator.

The Herati pattern is also in rugs from all over Iran. It derives from the town of Herat, now in Afghanistan but once part of the Persian empire. A central diamond shaped figure framed by four slightly curling leaves, is repeated several times. The Kurds use a similar pattern known as Mina Khani.

Weavers in Kerman sometimes include portraits in their designs, including such European celebrities as Napoleon and, of course, the Shahs and wealthy people of Iran.

The Iran Carpet Company has attempted to classify Persian carpet designs and to this end it has carried out studies of thousands of carpets. The results have shown that alterations were introduced into almost all original designs.
In its classification, the company has called the original design the main pattern and the derivatives the sub-patterns .